<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <!-- 判断成绩级别 -->
    <script>

        var score = parseInt(prompt("请输入您的成绩："));
        if(score >= 90){
            alert("您的成绩是A级！");
        }else if(score >= 80){
            alert("您的成绩是B级！");
        }else if(score >= 70){
            alert("您的成绩是C级！");
        }else if(score >= 60){
            alert("您的成绩是D级！");
        }else{
            alert("您的成绩是E级！");
            }

            
    </script>
</body>
</html>